Vitamin D 3 synthetic studies. Intramolecular Diels-Alder approaches to the CD-ring fragment
作者:Martin C. Clasby、Donald Craig、Albert A. Jaxa-Chamiec、Justine Y.Q. Lai、Andrew Marsh、Alexandra M.Z. Slawin、Andrew J.P. White、David J. Williams
DOI:10.1016/0040-4020(96)00147-0
日期:1996.3
The enantiospecific synthesis of the vitamin D3 CD ring fragment 3 is reported. Key steps are the diastereoselective allylation of a norephedrine/dihydrocitronellic acid-derived oxazolidinone, and the intramolecularDiels-Alder reaction of a sulfonyl-substituted dienyne. The analogous cycloaddition reaction of a trienylsulfone substrate is shown to give products having the incorrect stereochemistry